Fire control apparatus



FIRE CONTROL APPARATUS Filed July 20, 1940 TO C/FCU/T U/VZZE/i CONTROL FIXL'D Fill/7 TE R ELEME/W' 9 MVP/ FTTG. Z. M) Q bE/77ED HIGH TEMPEF/S'TUHE COEFFICIENT HE'S/v5 777N627 26 Bl-ME'I'A'LL/G ELEMENT WV -45 EGO 4. MG 5 Zinnentor 11 Perry l Jmvh/ ,1 Z Z &

be heat to the bimetallic element id of the capacitor C2, the element it will warp in either direction to assume the position of either Fig. -l or Fig. 5, depending upon the relative coeficients of expansion of the metals of which the element 83 is formed. In either case, it will be apparent that the capacity of the capacitor (33 will have been changed. 1

Connected to the plate 8, or in the output circuit of the tube i, is the winding L1 of a solenoid relay it the armature of which is arranged to cooperate with the movable element 2i of a switch in a circuit to be controlled and which may be arranged to cooperate with the aforementioned valve in the conduit i? or with other suitable mechanism for shutting off the supply of fuel to the flame it. In operation, the capacitor Cl. is manually adjusted to balance the arm I of the bridge against the arm 9. When heat is applied to the bimetallic electrode l3 by the flame or other suitable heat source is, it is obvious that the capacity of the capacitor C2 will change, whereupon the arms i and 9 of the bridge will become unbalanced and the tube 6 will be fired to energize the relay l9 and operate the switch element M. if the capacitor C2 is so arranged that its capacitance will decrease with a decrease in temperature, the resulting increase in impedance of the branch or arm 9 will make the grid 41 more pos itive and flre the tube. However, the reverse action is also possible, that is, the action can be reversed by making the capacitance of the capacitor C2 increase in capacity with decrease in temperature. In any event, it will be obvious that,

in my improved system, the tube 8 acts as a relay device with the bridge l-Q constituting a voltage divider for impressing an operating voltage on the grid 3 to fire the tube i when the element 63 has reached a predetermined temperature. Should the flame go out, the drop in temperature of the element It will restore the balance between the arms 7 and 9, and the tube i will shut down to deenergize the relay l9, whereupon'the switch element 2i will be returned to original position, as by a spring 22.

The arrangement of Fig. 2 is similar to that of Pig. 1, but in pl ce of the capacitors C1 and C2, I substitute a manually variable resistor R3 in the branch I and a heat responsive variable resistor Rt in the branch 9. The resistor R3 is preferably made of a material which has a zero temperature coefiicient', while the resistor R4 is made of a material having a high temperature coeihcient so that, when heat is applied to the resistor R4, its resistance will vary and the impedance of the branch 9 of the bridge will be altered. As in the case of th system of Fig. 1, that of Fig. 2 is initially set by adjusting the resistor R3 to balance the branch l against the branch 9. When a predetermined temperature has been reached, the resistance of the resistor R4 will have been suficiently altered to cause the tube l to fire and operate the relay it. When the heat source is removed from the resistor R4, its temperature will drop, the original impedance of the branch 9 will be restored to balance it against the branch I, and the tube I will go ofi.

The system of Fig. 3 is similar to those hereto fore described, but in this system I employ a pair of inductances L3 and L4, respectively, in the arms 7 and S. The incluctances L3 and La are provided with magnetite cores or the equivable, and the inductance L4 being adjustable in response to a bimetallic element 28 which is connected to the core thereof by a suitable cou-= pling 2d and which is responsive to the heat of the flame l5. Here, again, the system is orig inally set by manually adjusting the induct ance L3 to balance the arm 7 against the arm 9.

. When heat is applied to the bimetallic element 23, the inductance of the coil L4 will be changed to alter the impedance of the arm 9, whereupon the tube i will be fired and the relay is ener= gized. If the flame l5 goes out, the bimetallic element 23 is restored to its original position, the balance between the arms i and 9 is resumed, and the tube 8 becomes inoperative, whereupon the relay i9 isdeenergized and the switch element 2i restored to normal position by the spring 22.

From the foregoing description, it will be apparent to those skilled in the art that I have provided a novel flame control system which operates instantaneously, when certain predeter= In the circuit of Fig. l, v

mined conditions have been met, to control the flame. Although I have shown and described several embodiments of my invention, it is ap parent that various changes therein, as well as other modifications, are possible. For example, the grid voltage divider circuit, instead of being a capacitance, a resistance, or an inductance divider, may be a combination of resistance, capacitance and/or inductance, etc. Other changes will, no doubt, readily suggest themselves to those skilled in the art. I, therefore, desire that my invention shall not be limited except insofar as is made necessary by the prior art and by th spirit of the appended claims.

I claim as my invention: I 1. In flame responsive apparatus, the combination of an amplifier comprising an electron discharge device including a pair of bridge arms in the input circuit thereof, variable means in one of said arms associated with the flame and responsive to temperature changes induced thereby, and a relay in the output; circuit of said device associated with the fuel supply to said flame for controlling the supply of fuel to said flame, a predetermined temperature change resulting from said flame causing a variation in said variable means sumcient to alter the balance of said bridge arms whereby to actuate said relay to alter the fuel supply to said flame.

2. In flame responsive apparatus, the combination of an amplifier comprising an electron discharge device including a pair of bridge arms in the input circuit thereof, variable means in each of said arms adapted-ta be varied to efiect a balance of said arms, the variable means in one of said arms being manually adjustable and the variable means in the other of said arms being associated with the flame and responsive to temperature changes induced by said flame, and a relay in the output circuit of said device associated with the fuel supply to said flame for comtrolling the supply of fuel to said flame, a predetermined temperature change resulting from said flame causing a yariation in said secondnamed variable means 'sufiicient to. alter the balance of said bridge arms whereby to actuate said relay to alter the fuel supply to said flame.

3. In flame responsive apparatus, the combination of an amplifier comprising a cold cathode gaseous discharge device, a bridge having a pair of arms in the input circuit of said discharge de= vice. variable means in each of said arms for efiecting a balance of said arms, the variable means in one of said arms being manually adjustable and the variable means in the other of said arms being associated with the flame and responsive to temperature changes induced thereby, and a relay in the output circuit of said device associated with the fuel supply to said flame for controlling the supply of fuel thereto, a predetermined temperature change resulting from said flame causing a variation in said second-named variable means sufficient to alter the balance of said bridge arms whereby to actuate said relay to alter the supply of fuel to said flame.

4. In flame responsive apparatus, the combination of an amplifier comprising a cold cathode gaseous discharge device, a bridge having a pair of arms in the input circuit of said discharge device, variable means in each of said arms for altering the impedance thereof, one of said means being manually adjustable for adjustment of its arm into balancing relation with the other of said arms, the variable means in said other arm being associated with the flame and responsive to temperature changes induced thereby, and a relay in the output circuit of said device associated with the fuel supply to said flame for controlling the supply of fuel thereto, a predetermined temperature change resulting from said flame causing a variation in said second-named means to alter the impedance of its arm and thereby alter the balance of said bridge whereby to actuate said relay to alter the supply of fuel to saidv flame.

5. The invention set forth in claim i characterized in that said variable means comprise variable impedance elements.

6. The invention set forth in claim 4 character'- ized in that said variable means comprise variable capacitances.

"I. The invention set forth in claim a characterized in that said variable means comprise variable capacitances, and characterized further in that the second-named of said variable means comprises a capacitor one of the electrodes of which is constituted by a bimetallic element.

8. The invention set forth in claim 4 character- 1 ized in that said variable means comprise variable resistors.

9. The invention set forth in claim 4 character ized in that said first-named variable means comprises a variable resistor made of material havin substantially zero temperature coefficient, and characterized further in that said second-named variable means comprises a resistor made of material having a relatively high temperature coefficient.

10. The invention set forth in claim 4 characterized in that said variable means include variable inductances.

PERRY C. SMITH. 

